Holder for boring bars



Nov. 21, 1944.

L. L. WILLIAMS HOLDER FOR BORING BARS Filed Dec. 18, 1942 A it beingunderstood that bars of different sizes such as used in connection withlathes. v l l It frequently happens that holes of difierent Es PATENTorries j Y"2f,363,2l5 j" sandman Boimvcr BARS H i y ft iiieen.'w i sfria u.fi e-..

pui m aeata 1s, ie izkseriai uo.b 9391 *Th'is invention relatesjtbaholder desigried prl i marilyjior rigidly gripping'and supportingboring mental lugs-B proportioned to fit snugly within theupperportionpfithe slot B when the iofajse is properly'supported on therest A.

sizes must be formed in one piece of work and in order that bars ofdifferent sizes may be placed in position as needed and tightly grippedso as to prevent vibratiomthe present invention has been devised. i

A further object is to providea holder which is simple and compact inconstruction and can be readily assembled. I.

A further objectis to provide a holder capable of tightly grippingboring bars of different diam- The upper edge of the base I hasregularly spaced lugs 9 extending upwardly therefrom and preferablyrectangular. These lugs are adapted to fit snugly within correspondinglyshaped and proportioned notches or recesses l 0 formed in the l loweredge of a lower clamping member I I. This eters holding them firmlyagainst vibration and rotation.

With the foregoing and other objects in view which will appear asthedescription proceeds, the

ginvention consists ofycertain novel details of construction andcombinations of parts hereinafter more fully described andpointed out inthe claim,

changes may be made in the construction and arrangement of parts withoutdepartingfrom the spirit of the invention as In the accompanying drawingthe preferred form of the invention has been shown.

In said drawing: I Figure 1 is an elevation of the holder and a portionof the compound rest onwhich it is mounted,

a boring bar being shownin section.

Figure 2 is a section online 2-2, Figure 1, a

portion of the boring bar .tion. it

Figure 3 is a section on line 3-3, Figure 1. Figure .4 is a bottom planview of the holder. Referring to the figures by characters of reference,A designates the usual compound rest of a lathe provided with a slot Bsuch as commonly being shown in elevaemployed and the walls'ofw "ch areshaped to overhang and frictionally engage an insertible key I ed stem 2projecting upwardly therefrom and out of the slot B. I

A cylindrical core. 3 has a screw-threaded bore 4 extending 'intooneendfor engagement by the stem .2. while extending from the other end of thecore is a screw-threaded stem 5. The bore i 4 and stems 2 and 5 areco-axial with the longitudinal center of the core.

x The lower portion of the core is fitted snugly within a round opening6 extending through the v center of a base member 1 which is preferablycylindrical. This base member has opposed segmember is fitted snuglyupon the post 3 and cooperates with an upper clamping member I 2 whichis also fitted snugly about the post 3, the

A cylindricalopening I 4 is extended diametrically through the post 3and is sufficiently large to receive a boring bar 0 of the maximum sizeFormed in the upper to be held by thedevice. end of the member II andthe lower end of the member I2 are matching recesses l5. These recessescooperate to provide circular openings of different diameters any one ofwhich can be brought into alinement with the opening M. A I6 engagesstem 5 and by loosening this nut,

nut

theclamping member l2 can be lifted or]: of the post 3. .With the boringbar C out of position in the holder, the lower clamping member I I canbe raised a sufficient distance to release it from the studs 9 andthereafter this lower clamping mem ber can be rotated to bring intoalinement with i i the opening 14 the recesses l5 of proper size toreceive a boring bar of the size to be used. After this angularadjustment of the lowerwclamping provided at its center with ascrew-threadmember II has been effected, the boring bar of the selectedsize is inserted into theopening I 4 and the selected recesses IS. Theupper clamping member I2 is then lowered into position on the bar afterbeing adjusted to bring a recess l5 of correctsizeinto position to matcheach of the selected recesses l5 in the lower clamping member ll. Nut l6isnext tightened and this will cause the upper and lower clampingmembers to bind tightly upon the inserted boring bar and at the sametime pull thekey I upwardly so that the compound rest will be tightlygripped between this key and the lower portion of the base 1. Thus theboring bar will beheld rigidly in a parts II and I2 selected positionWhen it is desired to change toa boring bar of and will notturn orvibrate.

another size to be used on the same job, all that is necessary istounscrewthe; nut I6, lift the so that they are free to turn to lowerthese member after an opening of theselected size has been brought,

on post 3 and then into register with the opening I4. The boring bar ofthe selected size is then inserted and the parts again tightened asheretofore explained.

While this tool is designed primarily for hold- I ing boring bars asdescribed, it can also be employed advantageously on jobs requiringoutside turning and facing. I

Importance is attached to the fact that the parts can be assembledreadily and that the adjustment can be effected rigidly. Itis alsoimportant to note that any boring bar within certain limits of size,will be gripped firmly by the holder and thus held against vibrationwhile turning.

What is claimed is:

In a boring bar holder for lathes, to be received and held againstrotation in the a key shaped tation on the compound rest, upper andlower bar-clamping members rotatably and slidably mounted on the post,said members cooperating to provide regularly spaced openings therebetween arranged in pairs, the openings of each pair being diametricallyopposed and of a size differing from the openings of the other pairs,the pairs of openings between the clamping members being shaped toreceive boring bars of different diameters, means carried by the postfor moving the-upper clamping member toward the lower clamping member,to bind a boring bar in a selected pair of openings and cooperating,circum- A ferentially-arranged lugs and recesses on the lower clampingmember and on the base, and

holding the upper clamping member against ro- 'tation with respect tothe lower clamping memslot of the compound rest of a lathe, a threadedstem on the key, a post threaded'on the stem and having a diametricalopening for the reception of a boring bar, a base slidably and rotatablymounted on the post, means on the basefor insertion into the slot, tohold, the base against roberg-said lugs and recesses, the key, and a barwhich may be placed in a selected pair of openings, giving the upperclamping member an anchorage in the slot af lathe rest,- againstrotation. 5 LORAINE L. W-ILLIAMS.

